In its latest attempt to make its Web site more compelling, Yahoo Inc. is plugging its services into the rapidly growing craze of posting short messages, or "tweets," on Twitter.

Although Yahoo planned to announce the Twitter partnership Wednesday, most of the new features won't be available until later this year. Among other things, anyone with a Twitter account will be able to tweet and see the updates of people they're tracking while logged into Yahoo's Web site.

One change occurred Tuesday, when Yahoo started to show a wider range of Twitter updates in its search results - something that Google Inc. and Microsoft Corp. began doing late last year.

Celebrity Twitpics

Like its rivals, Yahoo is paying privately held Twitter an undisclosed amount of money for better access to its data.

Yahoo previously had been using Twitter's free tools to find tweets that pointed to the latest news about hot topics.

Unlike Google and Microsoft, Yahoo plans to turn its Web site into a tweeting perch. This follows Yahoo's recent commitment to tether its Web site to Facebook, which is even more widely used than Twitter.

Yahoo is hoping that these moves to build a network of social networks will make it easier for people to share information and images on Facebook and Twitter without leaving its Web site. And by giving people more reasons to stick around, Yahoo reasons it will have more chances to show the Internet ads that generate most of its revenue.

By some estimates, Facebook now attracts a bigger and more engaged audience than Yahoo. And Twitter has turned into a major communications channel that distributes an average of 50 million tweets per day, up from 2.5 million per day at the beginning of last year, according to the company's statistics.

The new Facebook connection on Yahoo is supposed to be available before July. Yahoo hasn't specified when people will be able to tweet from its site.